This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This program aims to determine the structures of proteins involved in cell membrane targeting, adhesion, and signaling, in order to establish the mechanism and specificity of their interactions. There are currently four projects with crystals that require synchrotron radiation. 1. Structure of full-length alpha-catenin, an F-actin binding protein that couples cadherin-based cell adhesion to regulation of the actin cytoskeleton. 2. The N-terminal domain of desmoplakin, a large protein that links desmosomal cadherins to intermediate filaments. 3. The Rab11 GTPase effector FIP3, involved in regulating targeting of recycling endosomal transport vesicles to the apical plasma membrane. 4. p97, a AAA+ ATPase responsible for removing misfolded proteins from the endoplasmic reticulum membrane, which also serves a model for the ATPase NSF responsible for disassembling SNARE complexes after membrane fusion.